1. Field of the Invention
The present invention relates to a multi-reactive polysiloxane compound having at least two halogen substituents and a synthetic method thereof and, more particularly, to a reactive siloxane compound and a synthetic method thereof in which the polysiloxane compound has at least two halogen substituents highly reactive to anion of living polymers such that addition of the polysiloxane compound in an anion polymerization reaction may enhance the heat resistance and abrasion resistance of the polymer, with improved compatibility with inorganic fillers and reinforcements used in rubber compositions and provide elastomers modified with organic silicon.
2. Description of the Related Art
Elastomers are excellent in readiness of synthesis and mechanical properties, including elasticity, and broadly used in various applications such as tires, parts of motorcar, impact absorbents, shoes and packing. Such elastomers have been developed for organic-inorganic composite materials, which are synthesized by mixing silica and glass fibers in vulcanization in order to provide enhanced heat resistance and strength.
Korean Patent Publication No. 96-008120, for example, discloses a styrene resin composition comprising 0.3 to 1.0 part by weight of polysiloxane, and glass fiber in addition to 100 parts by weight of a styrene resin composed of 20 to 70 parts by weight of amorphous polystyrene resin and 80 to 30 parts by weight of rubber-modified styrene resin. However, such an organic polymeric composite material, which is prepared by dispersion of polydimethylsiloxane, is susceptible to phase separation and incompatible with inorganic fillers due to no chemical bond between polydimethylsiloxane and organic polymer. Therefore, the composite material is hard to have the properties enhanced.
To solve the problem with the composite material in regard to compatibility of the polymer with inorganic fillers and siloxane, many studies have been made on those polymers that have siloxane substituents. For example, Korean Patent Laid-open No. 95-704405 discloses a method of adding hexamethylchlorotrisiloxane to the living group terminal of the polymer. This method may overcome the problem of phase separation but involve another problem that the polymer can not have higher molecular weight and enoughly enhance physical property from the existence of the siloxane substituents.
Therefore, there is a need of developing a highly reactive polysiloxane compound.
Polysiloxane with terminal or side reactive substituents is commonly added to coating, coupling agent, adhesive, sticking agent and sealant in order to enhance the mechanical properties of the coating surface against the medium, heat resistance, and compatibility. U.S. Pat. No. 5,858,468, for instance, discloses a composition comprising a polysiloxane having unsaturated groups and another polysiloxane having a Sixe2x80x94H groups, which coating composition cures at room temperature. U.S. Pat. No. 5,373,079 refers to a polydimethylsiloxane having alkoxy, acyloxy, N-methylbenzamido, or alkyl substituents. In U.S. Pat. No. 5,340,899, disclosed is a mixture that contains a polysiloxane having terminal hydroxyl groups and a silane having vinyl or methylacetamido groups, thereby effectively reducing the modulus of siloxane sealants. In addition, U.S. Pat. No. 5,194,553 describes an organofunctionl-terminated polydiorganosiloxane polymer and a preparation method for a copolymer thereof, which are specifically useful in preparation of 5-hexenyl-terminated polydimethylsiloxanes. The methods as stated in the cited reference include a method for preparing an organofunctionl-terminated polydiorganosiloxane polymer using an organofunctional chlorosilane end-blocker, and a method for preparing an organofunctionl-terminated polydiorganosiloxane copolymer using an organofunctional chlorosilane end-blocker and an organofunctional dichlorosilane. The organofunctionl-terminated polydiorganosiloxane polymer has the formula R1aRbSiO(R2SiO)xSiR1aRb, in which R is alkyl or aryl; R1 and R2 are independently alkenyl or haloalkyl; and a and b are integers satisfying the relationship a+b=3; and the organofunctional-terminated polydiorganosiloxane copolymer has the formula
R1aRfSiO{(R2SiO)x}y{(R2cR2dSiO)q}zSiR2cRf. 
The reactive siloxane or silane can also be substituted to the terminal or block of the polymer in order to enhance the mechanical properties and characteristics of the polymer. For example, a polymer substituted functional groups such as an olefinic chlorosilane and olefinic halide is described in U.S. Pat. No. 4,978,720, which polymer can be copolymerized with ethylene and alpha-olefinic monomers to form a modified polyolefin. In addition, Lucas in U.S. Pat. Nos. 4,599,394 (filed on Jul. 8, 1986) and 4,731,411 (filed on May 15, 1988) has reported a method for preparing a polysiloxane having terminal alkoxyl substituents, which polysiloxane is usable for a silicon rubber composition readily vulcanized at room temperature. Such a reactive polysiloxane, with at least two substituents, is reactive to at least two living groups of a polymer to form multi-substituted elastomers.
However, the polydimethylsiloxane is readily decomposed prior to reaction with the living groups of the polymer due to its low storage stability or not so reactive to anion of living polymers to participate in the multi-substitution.
Accordingly, there is a need for multi-reactive polysiloxanes containing polysiloxane groups and reactive to anion of living polymers.
In an attempt to solve the problems, the present inventors have studied on a method for preparing a polysiloxane macromer containing reactive groups and, particularly, a method for preparing a polysiloxane having at least two halogen substituents for multi-substitution.
It is, therefore, an objective of the present invention to provide a new halogen or alkyl-substituted reactive polysiloxane that is reactive to at least one equivalent of a polymer in an anionic polymerization reaction.
To achieve the above objective of the present invention, there is provided a halogen-substituted reactive polysiloxane compound with a number average molecular weight of 400 to 100,000 and the following formula 1, Yxe2x80x94{C(R3)(R4)}Cxe2x80x94CH2CH2xe2x80x94Si(R1)(R2)xe2x80x94{Oxe2x80x94Si(R1)(R2)}dxe2x80x94CH2CH2xe2x80x94{C(R3)(R4)}cxe2x80x94Y, in which Y is (X)a(R1)bSixe2x80x94, or (X)e(R1)fxe2x80x94Bzxe2x80x94C(R5)i(X)jxe2x80x94; X is a halogen selected from F, Cl, Br and I; R is an alkyl group from C1 to C20 including methyl, ethyl or propyl; R1, R3, R4 and R5 are a hydrogen, an alkyl group from C1 to C20 including methyl, ethyl or propyl, or a halogen-substituted alkyl or silane group; R2 as defined as R1, or (X)g(R3)hCxe2x80x94{C(R3)(R4)}cxe2x80x94; a is an integer from 1 to 3, and b is an integer from 0 to 2, wherein a+b=3; c is an integer from 0 to 1000; d is an integer from 1 to 50000; e and f are independently an integer from 0 to 4, wherein e+f=4; g and h are independently an integer from 0 to 3, wherein g+h=3; i and j are independently an integer from 0 to 3, wherein i+j=3; and Bz is a benzene ring.
The reactive polysiloxane compound of formula 1 is prepared by reacting a halogen-substituted vinyl compound represented by the following formula 2, Yxe2x80x94{C(R3)(R4)}cxe2x80x94CHxe2x95x90CH2, in which Y, X, R, R1, R3, R4, R5, and a to c and e, f, i and j are as defined as in formula 1, with a compound having Hxe2x80x94Si group represented by the following formula 3, Hxe2x80x94Si(R1)(R2)xe2x80x94{Oxe2x80x94Si(R1)(R2)}dxe2x80x94H, in which X, R1, R2, R3, R4, and c, d, g and h are as defined as in formula 1.
The present invention also provides a polysiloxane-substituted polymer containing at least 2 equivalents of a diene copolymer per a polysiloxane unit and having a number average molecular weight of 1,000 to 5,000,000, the polysiloxane-substituted polymer being prepared by reacting a living polymeric group of the diene copolymer with a reactive polysiloxane compound represented by formula 1.
Hereinafter, preferred embodiments of the present invention will be described in detail as follows.
The reactive polysiloxane having at least two halogen substituents as represented by formula 1 is prepared by reacting a vinyl or silicon compound having at least one halogen substituent as represented by formula 2 with a polysiloxane as represented by the formula 3 in the presence of a hydrosilylation catalyst.
Specific examples of the compound of formula 2 include trichlorovinyl silane, dichloromethylvinyl silane, chlorodimethylvinyl silane, and 4-trifluoromethyl styrene. Specific examples of the compound of formula 3 include a hydrogen-terminated polydimethyl siloxane. These compounds are synthesized by industrial method or commercially available from a manufacturing company such as Aldrich.
Examples of the hydrosilylation catalyst include chloroplatinic acid, transition metal selected from palladium, rhodium and platinum, and complex compounds, which are all commercially available from the manufacturing company such as Aldrich.
Examples of the reaction solvent as used herein may include, if not specifically limited to, organic solvents such as benzene and toluene.
The hydrosilylation temperature is in the range from xe2x88x9220xc2x0 C. to 150xc2x0 C., preferably, from room temperature to 120xc2x0 C. The hydrosilylation is conducted in the nitrogen atmosphere while stirring. The hydrosilylation time is not specifically limited and may be preferably in the range from about 30 minutes to one week.
After the completion of the reaction and removal of the solvent, the resulting material is purified to obtain the polysiloxane having at least two halogen substituents as represented by formula 1.
The polysiloxane of formula 1 according to the present invention has halogen groups highly reactive to anion of living polymers to form a covalent bond between the polymer and polysiloxane, and thus can be used in the preparation of a polysiloxane-modified polymer. Also, the polysiloxane block enhances compatibility with inorganic fillers such as silica, carbon black, metal oxides, metal powder, glass fiber, and other ceramics, and can be used for organic-inorganic hybrid composite materials.
In particular, the polysiloxane of the present invention is very soluble in normal organic solvents such as benzene, toluene, xylene, acetonitrile, sulfolane, propylene carbonate and acetone, and highly reactive to anion of living polymers generated by anionic initiators. The polymeric ions may include reaction products comprising monomers such as aromatic or aliphatic diene with unsaturated groups, or polysiloxane or cyclosiloxane.
Therefore, the polysiloxane prepared according to the present invention and an elastomer composition including the polysiloxane can be used for preparation of modified polymers, which is usable for compositions of various use purposes, such as conductive rubber, tire, adhesive, sticking agent, coating solution, sealant, and paint.
Hereinafter, the present invention will be described in detail by way of examples, which are not intended to limit the scope of the present invention.